Apparatus and method for switching power transmission mode of washing machine

ABSTRACT

An apparatus and method for switching a power transmission mode of a washing machine id disclosed, to prevent malfunction and damages of the washing machine by switching the power transmission mode stably in which the method includes: (a) rotating the cam ( 600 ) by driving the clutch motor ( 60 ); (b) counting the number of pulses of power supplied to the clutch motor ( 60 ); and (c) maintaining the rotation of the cam ( 600 ) until the ounted number of pulses is equal to, or greater than a preset number of pulses.

TECHNICAL FIELD

The present invention relates to a washing machine, and moreparticularly, to an apparatus and method for switching a powertransmission mode of a washing machine.

BACKGROUND ART

In general, the washing machine removes various dirt stuck to clothes,beddings, and the like by using softening action of detergent, frictioncaused by circulation of water coming from rotation of a pulsator, andimpact applied to the laundry by the pulsator, wherein an amount andkinds of laundry is detected with sensors, to set a washing methodautomatically, washing water is supplied appropriately according to theamount and kinds of the laundry, and the washing is carried out underthe control of a microcomputer.

A related art full automatic washing machine is operated in two methods,one of which is transmission of a rotation power from a driving motor toa washing shaft or a spinning shaft with a power transmission belt orpulley, for rotating the pulsator or a spinning tub, and the other ofwhich is rotating a washing and spinning tub at different speeds inwashing and spinning under the speed control of a brushless DC motor.

However, the related art washing machine has the process of switching apower transmission mode. In the related art washing machine, it isimpossible to sense a mechanical engagement state and a switching stateof a power transmission path during switching the power transmissionmode. In this respect, it may generate damages to components during awashing or spinning cycle.

DISCLOSURE OF INVENTION

An object of the present invention is to provide an apparatus and methodfor switching a power transmission mode of a washing machine, to preventmalfunction and damages of the washing machine by switching the powertransmission mode stably.

The object of the present invention can be achieved by providing anapparatus for switching a power transmission mode of a washing machinehaving a clutch including a coupling for selectively transmitting apower of a motor to a washing shaft and a spinning shaft, a clutch motorfor driving the coupling, and a cam fitted to be rotatable with theclutch motor for providing a switching signal in response to therotation; a power supplying part for supplying a voltage to the clutchmotor; a pulse counting part for counting the number of pulses of powersupplied to the clutch motor from the power supplying part; and a micomfor repeating rotation of the cam until the counted number of pulses isequal to, or greater than a preset number of pulses on driving theclutch motor.

At this time, the micom sets the alternate rotation power of the motoraccording to the amount of laundry and water level. That is, the micomsets the alternate rotation power of the motor to be higher as theamount of laundry is large and the water level is high, and the micomsets the alternate rotation power of the motor to be lower as the amountof laundry is small and the water level is low.

Also, the micom sets the alternate rotation power according to a voltageinputted to the motor. That is, the micom sets the alternate rotationpower of the motor to be lower as the voltage inputted to the motor ishigh, and the micom sets the alternate rotation power of the motor to behigher as the voltage inputted to the motor is low.

The micom rotates the motor alternately in left and right directionsaccording to a preset alternate rotation power before driving the clutchmotor and after stopping the clutch motor.

Also, the micom determines whether the motor is rotated when a power isreset, and the micom drives the clutch motor after rotation of the motoris stopped. Then. the micom turns off the power in case of that themotor is rotated after a lapse of a preset time period. Further, themicom drives the clutch motor, and simultaneously rotates the motoralternately in left and right directions.

In another aspect, a method for switching a power transmission mode of athrashing machine includes (a)rotating the cam by driving the clutchmotor; (b)counting the number of pulses of power supplied to the clutchmotor; and (c)maintaining the rotation of the cam until the countednumber of pulses is equal to, or greater than a preset number of pulses.

Also, the method further includes the steps of setting an alternaterotation power of the motor; and rotating the motor alternately in leftand right directions according to the set alternate rotation powerbefore the clutch motor is driven.

The alternate rotation power of the motor is set according to the amountof laundry and water level when setting the alternate rotation power ofthe motor.

The motor is rotated alternately in left and right directions at arotation angle smaller than a rotation angle in the washing and rinsingcycles.

Also, the method further includes the step of determining whether themotor is rotated in case of that a power is reset. At this time, thepower is turned off in case of that the motor is rotated after a lapseof a preset time period.

In another aspect, a method for switching a power transmission mode of awashing machine includes (a)rotating the cam by driving the clutchmotor; (b)determining whether the switch is switched; (c)maintaining therotation of the cam for a preset time period; and (d)stopping the clutchmotor.

At this time, the step of determining whether the switch is switchedincludes the steps of determining whether the switch is turned on incase of switching to a pulsator mode, and of determining whether theswitch is turned off in case of switching to a spinning tub mode.

Also, the step of maintaining the rotation of the cam for the presettime period includes the steps of counting the number of pulses of powersupplied to the clutch motor, and of comparing the counted number ofpulses with a preset number of pulses. Herein, the cam is rotatedcontinuously until the counted number of pulses is equal to, or greaterthan the preset number of pulses.

The method further includes the step of rotating the motor with a presetalternate rotation power before driving the clutch motor and afterstopping the clutch motor. Also, the alternate rotation power of themotor is set according to the amount of laundry and water level, or avoltage inputted to the motor.

BRIEF DESCRIPTION OF DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention, illustrate embodiment(s) of theinvention and together with the description serve to explain theprinciple of the invention. In the drawings;

FIG. 1 is a schematic view illustrating a general washing machine;

FIG. 2A and FIG. 2B are cross-sectional views illustrating a clutch anda motor of FIG. 1;

FIG. 3 is a perspective view illustrating a clutch motor according tothe present invention;

FIG. 4 is a disassembled perspective view of FIG. 3;

FIG. 5A to FIG. 5C illustrate an operational relation between a cam anda switch during driving a clutch motor;

FIG. 6 is a chart illustrating operations of a clutch motor, a cam and aswitch;

FIG. 7 is a block diagram illustrating an apparatus for switching apower transmission mode according to the present invention;

FIG. 8 is a flow chart illustrating a method for switching a powertransmission mode according to the first embodiment of the presentinvention;

FIG. 9 is a flow chart illustrating a method for switching a powertransmission mode according to the second embodiment of the presentinvention;

FIG. 10 is a flow chart illustrating a method for switching a powertransmission mode according to the third embodiment of the presentinvention; and

FIG. 11 is a flow chart illustrating a method for switching a powertransmission mode according to the fourth embodiment of the presentinvention.

BEST MODE FOR CARRYING OUT THE INVENTION

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. In describing the embodiments, same parts will be given thesame names and reference symbols, and repetitive description of whichwill be omitted.

FIG. 1 is a schematic view illustrating a general full automatic washingmachine.

Referring to FIG. 1, the full automatic washing machine includes a body1, an outer tub 2 a mounted in the body 1, and an inner tub 2 brotatably mounted in the outer tub 2 a. Also, there is a pulsator 3mounted on a central part of a bottom of an inside of the inner tub 2 b,the pulsator 3 rotating in left and right directions alternately inwashing and spinning cycles.

The full automatic washing machine also includes a spinning shaft 5 fortransmission of a rotation power to the inner tub 2 b, a washing shaft 4for transmission of a rotation power to the pulsator 3, and a clutch 6for transmission of a power of the motor 7 to either the washing shaft 4or the spinning shaft 5 depending on the washing or spinning cycle.

The clutch 6 has the following system. Referring to FIG. 2A and FIG. 2B,there is a clutch motor 60 under the outer tub 1, and a cam 600 mountedon a driving shaft 602 of the clutch motor 60. Also, there are a leverguide 30 fixed in a shaft support bearing case 20, and a lever 8 havinga recess 800 with a sloped surface 801, and a flat surface 801 extendedin a horizontal direction from a lower end of the sloped surface 801 formaking a linear motion guided by the lever guide 30 when the clutchmotor 60 is driven. There is a connecting rod 17 between the cam 600 andthe lever 8 of the clutch motor 60 for pulling the lever 8 toward theclutch motor 60 when the clutch motor 60 is turned on. Then, there is areturn spring 14 fastened between one end of the lever guide 30 and aprojection 803 from the lever 8, for giving a restoring force to thelever 8 when the lever 8 moves away from an end of the lever guide 30.There is a cylindrical hollow mover 9 for being engaged with the recess800 of the lever 8 in the spinning cycle, and moving down along thesloped surface 801 until the mover 9 stops at an underside of the flatsurface 802 in switching to a washing mode. There are a plunger 10fitted movable up/down along a guide groove 900 inside the mover 9, anda damping spring 11 between the mover 9 and the plunger 10. Also, thereis a coupling stopper 22 having gear teeth 221 formed along acircumferential direction of the shaft support bearing case 20 and fixedto an underside of the shaft support bearing case 20. There is afork-shaped rod 12 having a fore end of one side hinge-coupled with alower end of the plunger 10, and a point of a middle part hinge-coupledwith a lower end of a support bracket 220 formed below the couplingstopper 22, for making a seesaw movement around the point of the middlepart when the plunger 10 moves up/down. There is a coupling 15 fitted tobe movable up/down along the spinning shaft 5 for switching a rotationpower transmission path of the BLDC motor 7. There is a connectorassembly 16 for transmission of a rotation power of a rotor 7 b to thewashing shaft 4.

Referring to FIG. 3 and FIG. 4, the cam 600 is directly connected withthe driving shaft 602, whereby the cam 600 is rotated at a uniform speedwhen the driving shaft 602 is rotated, and the cam 600 also stops wherethe driving shaft 602 stops.

An operational relation between the cam 600 and the switch 650 will bedescribed as follows.

When the cam 600 is in a state consistent to an initial point, theswitch 650 is in a turning-off state. As shown in FIG. SC, the stateconsistent to the initial point of the cam 600 is a state that a rodconnecting shaft 601 of the cam 600 is at the initial point.

When it is intended to switch a power transmission path for washing, theclutch motor 60 is driven to turn the cam 600 in a counterclockwisedirection. Since a projection 650 a of the switch 650 is on a cam recesssurface 600 a until a rotation angle of the cam 600 reaches to 150° fromthe initial point, the switch 650 is in a turning-off state.

Thereafter, since the projection 650 a from the switch 650 leaves thecam recess surface 600 a as the rotation angle of the cam 600 reaches to150° from the initial point, the switch 650 is turned on. When therotation angle of the cam 600 reaches to 150° from the initial point,gear teeth 151 of the coupling 15 and the gear teeth 221 of the couplingstopper 22 come into engagement.

After that, referring to FIG. 5A, when the cam 600 reaches to a pointthat is at 170° from the initial point, the clutch motor 60 is made toturn off. The reason that the clutch motor 60 is made to turn off at apoint consistent to a maintaining point of the cam 600 is for more firmpower switch to the washing mode.

Meanwhile, in the spinning cycle after completing the washing cycle, itis required to return the cam 600 to a position consistent to theinitial point. For this, at the time of power switch to the spinningmode, the clutch motor 60 is turned on again, to turn the cam 600 in thecounterclockwise direction. In this instance, as shown in FIG. 5B, theswitch 650 maintains a turning-on state until the cam 600 passes a pointwhich is at 328° from the initial point in the counterclockwisedirection (a point 158° from the maintaining point in thecounterclockwise direction), when the projection 650 a from the switch650 comes to the cam recess surface 600 a, to turn off the switch 650.

Therefore, even if the switch 650 is turned off, the clutch motor 60maintains a turning-on state until the cam 600 reaches to a pointconsistent to the initial point under the control of the microcomputer,when the clutch motor 60 is turned off. In this instance, the number ofpulses of an AC power supplied to the clutch motor 60 is counted whilethe clutch motor 60 is maintained in the turning-on state starting froma time right after the switch 650 is turned off to a time the cam 600reaches to a point consistent to the initial point. By using the numberof the pulses, the clutch motor 60 is controlled.

In the meantime, in state of that the cam 600 is at the initial point,not only the gear teeth 151 of the coupling 15 and the gear teeth 221 ofthe coupling stopper 22 are disengaged, but also an upper serration 150a and a lower serration 150 b are engaged with a serration 161 b on anoutside circumferential surface of an upper part of an inner connector16 b and a serration on a lower part of the spinning shaft. 5respectively at the same time, whereby the spinning by simultaneousrotation of the washing shaft 4 and the spinning shaft 5 is carried out.

Referring to FIG. 2B, before starting the washing cycle, the clutch 6according to the present invention is in a turning-off state when nopower is applied to the clutch motor 60, and the coupling 15 is moveddown. At this time, the mover 9 is positioned in the recess 800 with thesloped surface 801 of the lever 8.

In this state, when power is applied to the clutch motor 60, to turn onthe clutch motor 60, driving power of the clutch motor 60 is transmittedto the cam 600, the connecting rod 17 moves toward the clutch motor 60as the cam 600 rotates, whereby the lever 8 is pulled toward the clutchmotor 60 along the lever guide 30. In this instance, the return spring14 provided in a rear end of the lever guide 30 is extended.

In the meantime, the mover 9 brought into contact with the slopedsurface 801 of the lever 8 when the cam 600 rotates, moves down alongthe sloped surface 801, until the mover 9 comes to the underside of theflat surface 802 of the lever 8, as shown in FIG. 2A, at a time the cam600 comes to the maintaining point.

While the mover 9 moves down according to rotation of the cam 600 andmovement of the lever 8 toward the clutch motor, the mover 9 compressesthe damping spring 11, whereby the plunger 10 fitted to be movable alongthe guide groove 900 also moves down.

Subsequently, as the plunger 10 moves down, the rod 12 hinge-coupledwith the plunger 10 rotates around a fastening pin 12 b at the point ofthe middle part of the rod 12 passing through the support bracket 220 ofthe coupling stopper 22 in the counterclockwise direction.

While the rod 12 rotates around the fastening pin 12 b in thecounterclockwise direction, an end of the rod 12 is brought into contactwith the lower part of the coupling 15, and pushes up the coupling 15along the spinning shaft 5 in an upper part of the shaft. Accordingly,as shown in FIG. 2A, when the power switch to the washing mode isfinished, the gear teeth 151 on the upper part of the coupling 15 areengaged with the gear teeth 221 on the coupling stopper 22.

When the gear teeth 151 on the coupling 15 are engaged with the gearteeth 221 on the coupling stopper 22, the coupling 15 is freed from theconnector assembly 16, such that only the washing shaft 4 rotates whenthe rotor 7 b rotates. That is, in the washing cycle, because thecoupling 15 is engaged only with the serration on the outsidecircumferential surface of the spinning shaft 5, but not with theserration on the upper part of the inner connector 16 b engaged with thewashing shaft 4, the rotation power is transmitted from the rotor 7 onlyto the pulsator 3 through the washing shaft 4.

In the state the gear teeth 151 on the coupling 15 are engaged with thegear teeth 221 on the coupling stopper 22, the gear teeth 221 on thecoupling stopper 22 prevent the coupling 15 from being rotated.

Referring to FIG. 2A, when the switch of a power transmission path tothe spinning tub mode is required for progressing spinning as thewashing is finished while the washing is progressed, power is applied tothe clutch motor 60 again, to drive the clutch motor 60, and rotate thecam 600.

When the cam 600 of the clutch motor 60 moves to a spinning position,the lever 8 moves away from the clutch motor 60 by a restoring force ofthe return spring 14. Accordingly, as shown in FIG. 2B, the mover 9being in contact with the flat surface 802 of the lever 8 is positionedin the recess 800 with the sloped surface 801 of the lever 8 at the timereturning of the lever 8 is finished.

As the mover 9 moves up according to the movement of the lever 8, thecompression on the damping spring 11 is eased, whereby the plunger 10moves up along the guide groove 900 in the mover 9. Following the moveup of the plunger 10, the rod 12 hinge-coupled to the plunger 10 turnsaround the fastening pin 12 b in a clockwise direction when the drawing(FIG. 2A) is seen from above.

Following the clockwise direction rotation of the rod 12 around thefastening pin 12 b, the force of an end of the rod 12 which supports thecoupling 15 is eliminated. Then, the coupling 15 moves down by gravityand the restoring force of the compression spring 40, whereby the gearteeth 151 of the coupling 15 is disengaged from the gear teeth 221 ofthe coupling stopper 22.

When the coupling 15 moves down fully, the serrations 150 a and 150 b onan inside circumferential surface of the coupling 15 are engaged withthe serration 161 b and the serration in a lower part of the spinningshaft 5, so that spinning is carried out as the spinning of the washingshaft 4 and the spinning shaft 5 are carried out at the time of spinningthe rotor 7 b.

Referring to FIG. 7, an apparatus for switching a power transmissionmode of a washing machine according to the present invention includes apower supplying part 71, a pulse counting part 72, a motor sensing part73, a microcomputer(hereinafter, micom) 100, a motor 7, a clutch 6, anda display part 700.

Referring to FIG. 3 and FIG. 4, the clutch 6 includes a clutch motor 60for moving up/down a coupling 15 proper to a washing or spinning cycle,and a cam 600 fitted to be rotatable with the clutch motor 60 forproviding a switching signal in response to the rotation.

The power supplying part 71 supplies a voltage to the motor 7 and theclutch motor 60, and the pulse counting part 72 counts the number ofpulses of an AC power supplied to the clutch motor 60 from the powersupplying part 71. Also, the motor sensing part 73 senses the rotationof the motor 7.

The micom 100 checks whether the cam 600 is driven within a preset timeperiod after driving the clutch motor 60. If the cam 600 is not drivenwithin the preset time period, the micom 100 turns off the clutch motor60, and puts the clutch motor 60 into operation again, and re-checkswhether the cam 600 is driven.

Also, if a user requires switching of the power transmission modemanually, the micom 100 senses the position of the cam 600, anddetermines whether the cam 600 is in a correct position. If it isdetermined that the cam 600 is in the correct position, the micom 100switches the power transmission mode. Then, the micom 100 controls thedisplay part 700 so as to display the switched power transmission mode,the engagement state between the gear teeth 151 of the coupling 15 andthe gear teeth 221 of the coupling stopper 22, and malfunctions thereof.

A method for switching a power transmission mode of a washing machineaccording to the present invention will be described as follows.

FIRST EMBODIMENT

In general, a washing machine is operated in two modes. One is apulsator mode employed in a washing or rinsing cycle, and the other is aspinning tub mode employed in a spinning cycle.

First, a switching process from the spinning tub mode to the pulsatormode will be described as follows.

When a voltage is applied to the washing machine, the washing machine isinitialized as the spinning tub mode, whereby it is required to switchthe spinning tub mode to the pulsator mode so as to perform the washingor rinsing cycle.

As shown in FIG. 8, the micom 100 determined whether it requires theswitching to the pulsator mode for the washing or rinsing cycle (S81).In case of that the washing machine is initialized, if the user requiresto perform the washing or rinsing cycle after performing or completingthe spinning cycle, the micom 100 determines that it requires theswitching to the pulsator mode.

If it is required to perform the switching to the pulsator mode, undercontrol of the micom 100, the BLDC motor 7 is alternately rotated inleft and right directions momentarily for N times (for example, fourtimes) or a preset time period (one to three seconds) at a rotationangle smaller than a rotation angle in the washing cycle.

The BLDC motor 7 is alternately rotated in left and right directions foreliminating a cause that impedes moving up of the coupling 15. Themoving up of the coupling 15 is impeded by surface pressures of theserrations 150 a and 150 b exerted to the serration on the lower part ofthe spinning shaft 5 and the serration 161 b on the upper part of theinner connector 16 b in opposite directions caused by opposite directionforces of the spinning shaft 5 and the inner connector 16 b engaged withthe coupling 15 at stopping of the washing machine. Therefore, beforeproceeding, to the step for moving up the coupling 15 to a position ofthe washing mode, the BLDC motor 7 is alternately rotated in left andright directions for eliminating the cause that impedes moving up of thecoupling 15.

After that, the micom 100 puts the clutch motor 60 into operation forrotating the cam 600 (S82). Then, the micom 100 determines whether theswitch 650 is turned on by the rotation of the cam 600 (S83). Theturning-on state of the switch 650 means that the gear teeth 151 of thecoupling 15 are engaged with the gear teeth 221 of the coupling stopper22. Therefore, by determining the turning-on state of the switch 650, itis possible to determine whether the engagement of the gear teeth 151 ofthe coupling 15 with the gear teeth 221 of the coupling stopper 22 isdone or not.

As a result of the determination in the step S83, if it is determinedthat the switch 650 is turned on, the pulse counting part 72 counts thenumber of pulses of the AC voltage supplied to the clutch motor 60 whilethe switch 650 is in the turning-on state. Then, the micom 100determines whether the counted number of pulses is greater than a presetnumber of pulses, for example, ‘66’ (S90).

As a result of the determination in the step S90, if the counted numberof pulses is smaller than the preset number of pulses, the steps S83 andS90 are repeated until the counted number of pulses is equal to, orgreater than the preset number of pulses. While the steps S83 and S90are repeated, the clutch motor 60 is driven continuously. Therefore, theengagement of the gear teeth 151 of the coupling 15 with the gear teeth221 of the coupling stopper 22 becomes more positive.

As a result of the determination in the step S90, if the counted numberof pulses of the AC voltage is equal to or greater than the presetnumber of pulses, the clutch motor 60 is stopped (S91), and the BLDCmotor 7 is alternately rotated in left and right directions momentarilyunder control of the micom 100. In this instance, the BLDC motor 7 isalternately rotated in left and right directions at an angle smallerthan an angle in washing for N times (for example, four times) or apreset time period (one to three seconds). The left and right directionalternate rotation is made for preventing the BLDC motor 7 from puttinginto operation in state of that the engagement of the gear teeth 151 ofthe coupling 15 with the gear teeth 221 of the coupling stopper 22 isnot perfectly caused by mechanical or motor malfunction, in advance.

On completing the switching to the pulsator mode, the micom 100 performsthe washing or rinsing cycle. After completing the washing or rinsingcycle, the washing machine is switched from the pulsator mode to thespinning tub mode so as to perform the spinning cycle. Usually, theswitching to the spinning tub mode is progressed after completing theswitching to the pulsator mode. However, it is possible to perform theswitching to the spinning tub mode during switching to the pulsator modeby the user's command.

Next, a process of switching from the pulsator mode to the spinning tubmode will be described as follows.

The micom 100 checks whether the user's command requiring the switchingto the spinning tub mode is inputted during switching to the pulsatormode (S84). As mentioned above, if the user's command is not inputted,the micom 100 progresses the steps S90 and S91 sequentially, so as tocomplete the switching, to the pulsator mode, and then the switching tothe spinning tub mode is progressed.

However, if the user's command for switching to the spinning tub mode isinputted during switching to the pulsator mode, the micom 100 checkswhether the counted number of pulses is equal to or greater than thepreset number of pulses, for example ‘66’ (S85).

As a result of the determination in the step S85, if the counted numberof pulses is smaller than the preset number of pulses, the step S85 isrepeated until the counted number of pulses is equal to, or greater thanthe preset number of pulses. Therefore, the engagement of the gear teeth151 of the coupling 15 with the gear teeth 221 of the coupling stopper22 becomes more positive. Simultaneously, it is possible to obtain thetime for correctly positioning the cam 600 at the initial point.

As a result of the determination in the step S85, if the number ofpulses of AC voltage is equal to or greater than the preset number ofpulses, the micom 100 considers that the cam 600 is positioned at theinitial point. After that, under control of the micom 100, the clutchmotor 60 is stopped, and the BLDC motor 7 is alternately rotated in leftand right directions at an angle smaller than an angle in washing for Ntimes (for example, four times) or a preset time period (one to threeseconds).

After that, the micom 100 puts the clutch motor 60 into operation forrotating the cam 600 (S86). Then, the micom 100 determines whether theswitch 650 is turned off by the rotation of the cam 600 (S87). Herein,the turning-off state of the switch 650 means that disengagement of thegear teeth 151 of the coupling 15 with the gear teeth 221 of thecoupling stopper 22. Therefore, by determining the turning-off state ofthe switch 650, it is possible to determine whether the disengagement ofthe gear teeth 151 of the coupling 15 with the gear teeth 221 of thecoupling stopper 92 is done or not.

As a result of the determination in the step S87, if it is determinedthat the switch 650 is turned off, the pulse counting part 72 counts thenumber of pulses of the AC voltage supplied to the clutch motor 60 whilethe switch 650 is in the turning-off state. Then, the micom 100determines whether the counted number of pulses is greater than a presetnumber of pulses, for example, ‘66’ (S88).

As a result of the determination in the step S88, if the counted numberof pulses is smaller than the preset number of pulses, the processproceeds back to the step S87. Then, the steps S87 and S88 are repeateduntil the counted number of pulses is equal to, or greater than thepreset number of pulses. While the steps S87 and S88 are repeated, theclutch motor 60 is driven continuously Accordingly, the disengagement ofthe gear teeth 151 of the coupling 15 with the gear teeth 221 of thecoupling stopper 22 becomes perfect.

In opposite to this, as a result of the determination in the step S88,if the counted number of pulses of the AC voltage is equal to, orgreater than the preset number of pulses, the clutch motor 60 is stopped(S89), and the BLDC motor 7 is alternately rotated in left and rightdirections momentarily under the control of the micom 100. In thisinstance, the BLDC motor 7 is alternately rotated in left and rightdirections at an angle smaller than an angle in washing for N times (forexample, four times) or a preset time period (one to three seconds). Thefour times of left and right direction alternate rotation is made forpreventing the BLDC motor 7 from putting into operation in state of thatthe disengagement of the gear teeth 151 of the coupling 15 with the gearteeth 221 of the coupling stopper 22 is not perfect due to mechanical ormotor malfunction, in advance. As mentioned above, after completing theswitching to the spinning tub mode, the micom 100 performs the spinningcycle.

SECOND EMBODIMENT

FIG. 9 is a flow chart illustrating a method for switching a powertransmission mode of a washing machine according to the secondembodiment of the present invention. In the method for switching thepower transmission mode of the washing machine according to the secondembodiment of the present invention, it is possible to stably switch thepower transmission mode when a power of the washing machine is resetduring driving the washing machine.

While the washing machine performs a washing, rinsing or spinning cycle,if the power is reset according to a user or a malfunction, the micom100 checks whether the power is reset (S101).

If it is determined that the power is reset, under control of the micom100, the motor sensint part 73 checks whether the BLDC motor 7 isrotated (S102). The micom 100 receives data regarding the rotation ofthe BLDC motor 7 from the motor sensing part 73. That is, the micom 100checks whether a rotation speed of the BLDC motor 7 is ‘0’ from thedata.

If it is determined that the BLDC motor 7 is rotated, the micom 100senses the BLDC motor 7 for a preset time period. For example, if theBLDC motor 7 is not stopped after passage of ten minutes, the micom 100controls the display part 700 to display an error message, therebyinforming the malfunction of the washing machine to the user.Accordingly, the power is turned off.

If it is determined that the BLDC motor 7 is not rotated, the micom 100starts to switch the power transmission mode. That is, if the rotationof the BLDC motor 7 is stopped in the preset time period, the micom 100starts to switch the power transmission mode.

For switching to the pulsator mode, the micom 100 puts the clutch motor60 into operation (S103). At this time, the cam 600 is rotated accordingto the clutch motor 60. Also, the micom 100 determines whether theswitch 650 is turned on by the rotation of the cam 600 (S104). Bydetermining whether the switch 650 is in the turning-on state, it ispossible to check whether the gear teeth 151 of the coupling 15 areengaged with the gear teeth 221 of the coupling stopper 22.

As a result of the determination in the step S104, if it is determinedthat the switch 650 is not in the turning-on state, the micom 100 checksrepetitively whether the switch 650 is turned on.

As a result of the determination in the step S104, if it is determinedthat the switch 650 is in the turning-on state, the pulse counting part72 counts the number of pulses of AC voltage supplied to the clutchmotor 60 while the switch 650 is in the turning-on state. The micom 100determines whether the counted number of pulses is greater than a presetnumber of pulses, for example, ‘66’ (S105).

As a result of the determination in the step S105, if the counted numberof pulses is smaller than the preset number of pulses, the steps S104and S105 are repeated until the counted number of pulses is equal to, orgreater than the preset number of pulses. At this time, the clutch motor60 is driven continuously while the steps S104 and S105 are repeated.

As a result of the determination in the step S105, if the number ofpulses of AC voltage is equal to, or greater than the preset number ofpulses, the clutch motor 60 is stopped under control of the micom 100(S106).

As mentioned above, after completing the switching to the pulsator mode,the switching to the spinning tub mode is progressed. In case of thatthe user desires to perform the washing or rinsing cycle after resettingthe power, the micom 100 performs the washing or rinsing cycle afterswitching the pulsator mode to the spinning tub mode.

For switching the pulsator mode to the spinning tub mode, the micom 100drives the clutch motor 60 (S107). At this time, the cam 600 is rotatedaccording to the clutch motor 60. Also, the micom 100 determines whetherthe switch 650 is turned off by the rotation of the cam 600 (S108). Bydetermining whether the switch 650 is turned off, it is possible todetermine whether the gear teeth 151 of the coupling 15 are disengagedwith the gear teeth 221 of the coupling stopper 22.

As a result of the determination in the step S 108, if it is determinedthat the switch 650 is turned off, the pulse counting part 72 counts thenumber of pulses of AC voltage supplied to the clutch motor 60 while theswitch 650 is turned off. Then, the micom 100 determines whether thecounted number of pulses is greater than a preset number of pulses, forexample, ‘66’ (S109).

As a result of the determination in the step S109, if the counted numberof pulses is smaller than the preset number of pulses, the processproceeds back to the step S108. Then, the steps S 108 and S109 arerepeated until the counted number of pulses is equal to, or greater thanthe preset number of pulses. At this time, the clutch motor 60 is drivencontinuously while the steps S108 and S109 are repeated.

As a result of the determination in the step S109, if the number ofpulses of AC voltage is equal to, or greater than the preset number ofpulses, the clutch motor 60 is stopped under control of the micom 100(S110). Herein, the clutch motor 60 is stopped at a point of completingthe switching to the spinning tub mode and starting the switching to thepulsator mode, simultaneously.

As mentioned above, after completing the pulsator mode to the spinningtub mode, if the user's command requiring the washing or rinsing cycleis inputted to the micom 100, the micom 10 switches the spinning tubmode to the pulsator mode, thereby performing the washing or rinsingcycle.

THIRD EMBODIMENT

FIG. 10 is a flow chart illustrating a method for switching a powertransmission mode according to the third embodiment of the presentinvention. For performing the washing or rinsing cycle, it is requiredto operate the washing machine in the pulsator mod. Meanwhile, in orderto perform the spinning cycle, it is required to operate the washingmachine in the spinning tub mode. Accordingly, the micom 100 switchesthe mode of the washing machine according to the respective washing,rinsing and spinning cycles.

As shown in FIG. 10, the micom 100 determines that the washing machineis operated in the pulsator mode or the spinning tub mode (S111). Incase of that the washing machine is initialized, and the user desires toperform the washing or rinsing cycle after progressing or completing thespinning cycle, the micom 100 determines that it requires the switchingto the pulsator mode. After completing the washing and rinsing cycles,the micom 100 determines that it requires the switching to the spinningtub mode.

As a result of the determination in the step S111, if it is determinedthat it requires the switching to the pulsator mode, the micom 100 setsthe alternate rotation power of the BLDC motor 7 (S112). The alternaterotation power means the power of the BLDC motor 7 for being alternatelyrotated in left and right directions. That is, the alternate rotationpower of the BLDC motor 7 is classified into various levels according tothe amount of laundry and water level in the inner tub of the washingmachine, or according to the voltage inputted to the BLCD motor 7.Accordingly, the micom 100 sets the alternate rotation power of the BLCDmotor 7 according to the water level in the inner tub and the amount oflaundry, or the input voltage.

In case of that the alternate rotation power is set on the basis of thewater level and the amount of laundry, if the water level is high or theamount of laundry is large, the alternate rotation power increases.Meanwhile, if the water level is low or the amount of laundry is small,the alternate rotation power decreases. For example, if the amount oflaundry is ‘large’, it is required to set the alternate rotation powerof the BLDC motor 7 as maximum. If the amount of laundry is ‘middle’, itis required to set the alternate rotation power of the BLDC motor 7 asmiddle, and if the amount of laundry is ‘low’, it is required to set thealternate rotation power of the BLDC motor 7 as minimum.

In case of that the alternate rotation power is set on the basis of thevoltage inputted to the BLDC motor 7, if the input voltage is high, thealternate rotation power decreases, and, if the input voltage is low,the alternate rotation power increases, thereby alternately rotating theBLDC motor 7 without regard to variety of input voltage. For example, ifthe input voltage is at 310V, the alternate rotation power of the BLDCmotor 7 is set as minimum. Meanwhile, if the input voltage is at 300V,the alternate rotation power of the BLDC motor 7 is set as middle. Also,if the input voltage is at 250V, the alternate rotation power of theBLDC motor 7 is set as minimum.

After setting the alternate rotation power of the BLDC motor 7, undercontrol of the micom 100, the BLDC motor 7 is alternately rotated inleft and right directions momentarily for N times (for example, fourtimes) or a preset time period (one to three seconds) at a rotationangle smaller than a rotation angle in the washing cycle.

Then, the micom 100 puts the clutch motor 60 into operation so as torotate the cam 600 after alternately rotating the BLDC motor 7 (S114).Also, the micom 100 determines whether the switch 650 is turned on bythe rotation of the cam 600 (S115). By determining whether the switch650 is turned on, it is possible to check whether the gear teeth 151 ofthe coupling 15 are engaged with the gear teeth 221 of the couplingstopper 22.

As a result of the determination in the step S115, if it is determinedthat the switch 650 is not in the turning-on state, the micom 100repetitively checks whether the switch 650 is turned on.

As a result of the determination in the step S115, if it is determinedthat the switch 650 is in the turning-on state, the pulse counting part72 counts the number of pulses of AC voltage supplied to the clutchmotor 60 while the switch 650 is turned on. Then, the micom 100determines whether the counted number of pulses is greater than a presetnumber of pulses, for example, ‘66’ (S116).

As a result of the determination in the step S116, if the counted numberof pulses is smaller than the preset number of pulses, the steps S115and S116 are repeated until the counted number of pulses is equal to, orgreater than the preset number of pulses. Herein, the clutch motor 60 iscontinuously driven while the steps S115 and S116 are repeated.Accordingly, the engagement of the gear teeth 151 of the coupling 15with the gear teeth 221 of the coupling stopper 22 becomes morepositive.

As a result of the determination in the step S116, if the number ofpulses of AC voltage is equal to, or greater than the preset number ofpulses, the clutch motor 60 is stopped (S117) under control of the micom100. After that, the BLDC motor 7 is alternately rotated in left andright directions according to the preset rotation power (S118). In thiscase, the BLDC motor 7 is alternately rotated in left and rightdirections momentarily for N times (for example, four times) or a presettime period (one to three seconds) at a rotation angle smaller than arotation angle in the washing cycle.

As mentioned above, after completing the switching to the pulsator mode,the micom 100 performs the washing or rinsing cycle. After completingthe washing or rinsing cycle, the washing machine switches the pulsatormode to the spinning tub mode so as to perform the spinning cycle.Usually, the switching to the spinning tub mode is progressed aftercompleting the switching to the pulsator mode. However, it is possibleto progress the switching to the spiraling tub mode during switching tothe pulsator mode by the user's command.

As a result of the determination in the step S111, if it is determinedthat it requires the switching to the spinning tub mode, the micom 100sets the alternate rotation power of the BLDC motor 7 (S119). Afterdischarging the washing water used in the washing or rinsing cycle, thespinning cycle is progressed. In this respect, the alternate rotationpower of the BLDC motor 7 for the spinning cycle is classified intovarious levels according to the amount of laundry absorbing the washingwater therein, or according to the voltage inputted to the BLDC motor 7.That is, the micom 100 sets the alternate rotation power according tothe amount of laundry or the input voltage.

In case of that the alternate rotation power is set according to theamount of laundry, if the amount of laundry is large, it is required toincrease the alternate rotation power. Meanwhile, the amount of laundryis small, it is required to decrease the alternate rotation power. Thus,the BLDC motor 7 is alternately rotated in left and right directions ata uniform speed without regard to a weight of laundry.

The case of setting the alternate rotation power of the BLDC motor 7according to the voltage inputted to the BLDC motor 7 will be describedwith reference to the step S112.

If the alternate rotation power of the BLDC motor 7 is set, the BLDCmotor 7 is alternately rotated in left and right directions momentarilyfor N times (for example, four times) or a preset time period (one tothree seconds) according to the preset alternate rotation power. Herein,the BLDC motor 7 is rotated at a rotation angle smaller than a rotationangle in the washing cycle.

After rotating the BLDC motor 7 alternately in left and rightdirections, the micom 100 puts the clutch motor 60 into operation so asto rotate the cam 600 (S121). Then, the micom 100 determines whether theswitch 650 is turned off by the rotation of the cam 600 (S122). Bydetermining whether the switch 650 is turned off, it is possible todetermine whether the engagement of the gear teeth 151 of the coupling15 with the gear teeth 221 of the coupling stopper 22 is done or not.

As a result of the determination in the step S122, if it is determinedthat the switch 650 is turned off, the pulse counting part 72 counts thenumber of pulses of AC voltage supplied to the clutch motor 60 while theswitch 650 is in the turning-off state. Then, the micom 100 determineswhether the counted number of pulses is greater than a preset number ofpulses, for example, ‘66’ (S123).

As a result of the determination in the step S123, if the counted numberof pulses is smaller than the preset number of pulses, the processprogresses back to the step S122. Then, the steps S122 and S123 arerepeated until the counted number of pulses is equal to, or greater thanthe preset number of pulses. La this state, the cultch motor 60 isdriven continuously while the steps S122 and S123 are repeated.Accordingly, the gear teeth 151 of the coupling 15 are disengaged withthe gear teeth 221 of the coupling stopper perfectly.

As a result of the determination in the step S123, if the number ofpulses of AC voltage is greater than the preset number of pulses, theclutch motor 60 is stopped under control of the micom 100. After that,the BLDC motor 7 is alternately rotated in left and right directionaccording to the alternate rotation power set in the step S119. Herein,the BLDC motor 7 is alternately rotated in left and right directionsmomentarily for N times (for example, four times) or a preset timeperiod (one to three seconds) at a rotation angle smaller than arotation angle in the washing cycle. As mentioned above, aftercompleting the switching to the spinning tub mode, the micom 100performs the spinning cycle.

FOURTH EMBODIMENT

FIG. 11 is a flow chart illustrating a method for switching a powertransmission mode of a washing machine according to the fourthembodiment of the present invention.

As shown in FIG. 11, the micom 100 determines that the washing machineis operated in the pulsator mode or the spinning tub mode (S131). Incase of that the washing machine is initialized, and the user desires toperform the washing or rinsing cycle after progressing or completing thespinning cycle, the micom 100 determines that it requires the switchingto the pulsator mode. After completing the washing and rinsing cycles,the micom 100 determines that it requires the switching to the spinningtub mode.

As a result of the determination in the step S131, if it is determinedthat it requires the switching to the pulsator mode, under control ofthe micom 100, the BLDC motor 7 is alternately rotated in left and rightdirections momentarily for N times (for example, four times) or a presettime period (one to three seconds) at a rotation angle smaller than arotation angle in the washing cycle.

After alternately rotating the BLDC motor 7, the micom 100 puts theclutch motor 60 into operation so as to rotate the cam 600, and rotatesthe BLDC motor 7 alternately in left and right directions for M times,simultaneously (S133). Then, the micom 100 determines whether the switch650 is turned on by the rotation of the cam 600 (S134). By determiningwhether the switch 650 is turned off, it is possible to determinewhether the gear teeth 151 of the coupling are engaged with the gearteeth 221 of the coupling stopper 22.

As a result of the determination in the step S134, if it is determinedthat the switch 650 is not in the turning-on state, the micom 100repetitively determines whether the switch 650 is turned on. As a resultof the determination in the step S134, if it is determined that theswitch 650 is in the turning-on state, the pulse counting part 72 countsthe number of pulses of AC voltage supplied to the clutch motor 60 whilethe switching 650 is in the turning-on state. Then, the micom 100determines whether the counted number of pulses is greater than a presetnumber of pulses, for example, ‘66’ (S135).

As a result of the determination in the step S135, if the counted numberof pulses is smaller than the preset number of pulses, the steps S134and S135 are repeated until the counted number of pulses is equal to, orgreater than the preset number of pulses. In this case, the clutch motor60 is continuously driven while the steps S134 and S135 are repeated.Accordingly, the engagement of gear teeth 151 of the coupling 15 withthe gear teeth 221 of the coupling stopper 22 becomes more positive.

As a result of the determination in the step S135, if the number ofpulses of AC voltage is equal to, or greater than the preset number ofpulses, the clutch motor 60 is stopped under control of the micom 100.After that, the BLDC motor 7 is rotated alternately in left and rightdirections according to the preset alternate rotation power (S137). Atthis time, the BLDC motor 7 is alternately rotated in left and rightdirections momentarily for N times (for example, four times) or a presettime period (one to three seconds) at a rotation angle smaller than arotation angle in the washing cycle.

The BLDC motor 7 is rotated alternately in left and right direction inthe step S132, S133 and S137. In the respective steps S132, S133 andS137, it is possible to differently set the alternate rotation power ofthe BLDC motor 7.

As a result of the determination in the step S131, if it is determinedthat it requires the switching to the spinning tub mode, under controlof the micom 100, the BLDC motor 7 is alternately rotated in left andright directions momentarily for N times (for example, four times) or apreset time period (one to three seconds) at a rotation angle smallerthan a rotation angle in the washing cycle.

After rotating the BLDC motor 7 alternately in left and rightdirections, the micom 100 puts the clutch motor 60 into operation so asto rotate the cam 600, and rotates the BLDC motor 7 alternately in leftand right direction for M times, simultaneously (S139). Then, the micom100 determines whether the switch 650 is turned off by the rotation ofthe cam 600 (S140). By determining whether the switch 650 is turned off,it is possible to determine whether the gear teeth 151 of the coupling15 are disengaged with the gear teeth 221 of the coupling stopper 22.

As a result of the determination in the step S140, if it is determinedthat the switch 650 is turned off, the pulse counting part 72 counts thenumber of pulses of AC voltage supplied to the clutch motor 60 while theswitch 650 is turned off. Then, the micom 100 determines whether thecounted number of pulses is greater than a preset number of pulses, forexample, ‘66’ (S141).

As a result of the determination in the step S141, if the counted numberof pulses is smaller than the preset number of pulses, the processprogresses back to the step S140. Then, the steps S140 and S141 arerepeated until the counted number of pulses is equal to, or greater thanthe preset number of pulses. In this case, the clutch motor 60 iscontinuously driven while the steps S140 and S141 are repeated.Accordingly, the gear teeth 151 of the coupling 15 are disengaged withthe gear teeth 221 of the coupling stopper 22 perfectly.

As a result of the determination in the step S141, if the number ofpulses of AC voltage is equal to, or greater than the preset number ofpulses, the clutch motor 60 is stopped under control of the micom 100(S142). After that, the BLDC motor 7 is rotated alternately in left andright directions (S143). Herein, the BLDC motor 7 is alternately rotatedin left and right directions momentarily for N times (for example, fourtimes) or a preset time period (one to three seconds) at a rotationangle smaller than a rotation angle in the washing cycle.

As mentioned above, after completing the switching to the spinning tubmode, the micom 100 progresses the spinning cycle.

The BLDC motor 7 is rotated alternately in left and right directions inthe respective steps S138, S139 and S143. In the respective steps S13S,S139 and S143, it is possible to differently set the alternate rotationpower of the BLDC motor 7.

INDUSTRIAL APPLICABILITY

As mentioned above, the apparatus and method for switching the powertransmission mode of the washing machine according to the presentinvention has the following advantages.

In the apparatus and method for switching the power transmission mode ofthe washing machine according to the present invention, it is possibleto check the position of the cam according to the state of the switch,whereby it is possible to position the cam at the correct initial pointwhen switching the power transmission mode.

Also, the BLDC motor is rotated alternately in left and right directionsmomentarily, whereby it is possible to engage or disengage the gearteeth of the coupling with the gear teeth of the coupling stopperperfectly. Accordingly, when switching the power transmission mode, itis possible to prevent components of the washing machine from beingdamaged, and to stably switch the power transmission mode.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the spirit or scope of the invention. Thus, it isintended that the present invention cover the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

1. An apparatus for switching a power transmission mode of a washingmachine comprising: a coupling for selectively transmitting a power of aBLDC motor to a washing shaft and a spinning shaft via a couplingstopper; a clutch including a clutch motor for moving up/down thecoupling by driving a cam, the cam fitted to be rotatable with theclutch motor and having a cam recess surface, and a switch contactingthe cam recess surface for providing a switching signal in response tothe rotation of the clutch motor; a motor sensing part for sensing therotation of the BLDC motor; a power supplying part for supplying avoltage to the clutch motor; a pulse counting part for counting thenumber of pulses of power supplied to the clutch motor from the powersupplying part when the switching signal of the switch is provided; anda micom for repeating rotation of the cam until the counted number ofpulses is equal to, or greater than a preset number of pulses on drivingthe clutch motor and for checking whether the power of the BLDC motor isreset by data provided from the motor sensing part.
 2. The apparatus asclaimed in claim 1, wherein the micom rotates the motor alternately inleft and right directions according to a preset alternate rotation powerbefore driving the clutch motor and after stopping the clutch motor. 3.The apparatus as claimed in claim 2, wherein the micom sets thealternate rotation power of the motor according to the amount of laundryand water level.
 4. The apparatus as claimed in claim 3, wherein themicom sets the alternate rotation power of the motor to be higher as theamount of laundry is large and the water level is high, and the micomsets the alternate rotation power of the motor to be lower as the amountof laundry is small and the water level is low.
 5. The apparatus asclaimed in claim 2, wherein the micom sets the alternate rotation poweraccording to a voltage inputted to the motor.
 6. The apparatus asclaimed in claim 5, wherein the micom sets the alternate rotation powerof the motor to be lower as the voltage inputted to the motor is high,and the micom sets the alternate rotation power of the motor to behigher as the voltage inputted to the motor is low.
 7. The apparatus asclaimed in claim 1, wherein the micom determines whether the motor isrotated when a power is reset.
 8. The apparatus as claimed in claim 7,wherein the micom turns off the power in case of that the motor isrotated after a lapse of a preset time period.
 9. The apparatus asclaimed in claim 7, wherein the micom drives the clutch motor afterrotation of the motor is stopped.
 10. The apparatus as claimed in claim1, wherein the micom drives the clutch motor, and simultaneously rotatesthe motor alternately in left and right directions.
 11. The apparatus asclaimed in claim 1, wherein the switch outputs a switching signal for aturning-on state so as to perform a switch to a power transmission modefor washing and rinsing cycles.
 12. The apparatus as claimed in claim 1,wherein the switch outputs a switching signal for a turning-off state soas to perform a switch to a power transmission mode for a spinningcycle.